MilliporeSigma

Sulfur-mediated electron shuttling during bacterial iron reduction.

Science (New York, N.Y.) (2014-05-03)
Theodore M Flynn, Edward J O'Loughlin, Bhoopesh Mishra, Thomas J DiChristina, Kenneth M Kemner
ABSTRACT

Microbial reduction of ferric iron [Fe(III)] is an important biogeochemical process in anoxic aquifers. Depending on groundwater pH, dissimilatory metal-reducing bacteria can also respire alternative electron acceptors to survive, including elemental sulfur (S(0)). To understand the interplay of Fe/S cycling under alkaline conditions, we combined thermodynamic geochemical modeling with bioreactor experiments using Shewanella oneidensis MR-1. Under these conditions, S. oneidensis can enzymatically reduce S(0) but not goethite (α-FeOOH). The HS(-) produced subsequently reduces goethite abiotically. Because of the prevalence of alkaline conditions in many aquifers, Fe(III) reduction may thus proceed via S(0)-mediated electron-shuttling pathways.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Carbonyl iron, ≥97% Fe basis
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Iron, foil, light tested, 25x25mm, thickness 0.01mm, 99.99+%
Iron, foil, 6mm disks, thickness 0.009mm, 99.85%
Iron, foil, 8mm disks, thickness 0.025mm, as rolled, 99.99+%
Iron, foil, 50mm disks, thickness 0.125mm, hard, 99.5%
Iron, foil, light tested, 25x25mm, thickness 0.025mm, as rolled, 99.99+%
Iron, foil, 5m coil, thickness 0.038mm, hard, 99.5%
Iron, foil, not light tested, 100x100mm, thickness 0.015mm, 99.85%
Iron, foil, 8mm disks, thickness 0.005mm, 99.85%
Iron, foil, 8mm disks, thickness 1.0mm, as rolled, 99.5%
Iron, foil, 6mm disks, thickness 0.003mm, 99.85%
Iron, foil, light tested, 50x50mm, thickness 0.075mm, hard, 99.5%
Iron, foil, 8mm disks, thickness 0.0125mm, 99.85%
Iron, foil, 8mm disks, thickness 0.125mm, as rolled, 99.99+%
Iron, foil, 5m coil, thickness 0.025mm, hard, 99.5%
Iron, foil, 6mm disks, thickness 0.015mm, 99.85%
Iron, foil, not light tested, 100x100mm, thickness 0.0125mm, 99.99+%
Iron, foil, light tested, 150x150mm, thickness 0.05mm, hard, 99.5%
Iron, foil, 8mm disks, thickness 0.9mm, as rolled, 99.5%
Iron, foil, light tested, 25x25mm, thickness 0.01mm, 99.85%